Field of the Invention
The invention relates to flash memories, and in particular to embedded flash (e-flash) memories having a floating gate with sharp tips and methods for manufacturing the same.
Description of the Related Art
A flash memory is a kind of non-volatile memory (NVM). Generally, a flash memory comprises two gates, the first gate is a floating gate (FG) for data storage and the second gate is a control gate for data input/output. The floating gate is placed under the control gate and “floats”. Floating refers to isolating the floating gate and surrounding it with insulating materials for preventing charge loss. The control gate is connected to a word line (WL) for device control. One advantage of flash memories is block-by-block erasing. Flash memory is widely used in enterprise servers, storage and networking technology, and a wide range of consumer electronic products, such as USB flash drives, mobile phones, digital cameras, tablet computers, PC cards in notebook computers, and embedded controllers, for example.
There are several kinds of non-volatile memory available in the market, such as flash memory, electrically erasable programmable read-only memory (EEPROM) and multi-time programmable (MTP) non-volatile memory. However, embedded flash (e-flash) memory and especially embedded split-gate flash memory shows dominance over other non-volatile memory technologies.
Although existing flash memories and methods for manufacturing the same have been adequate for their intended purposes, they have not been entirely satisfactory in all respects. Therefore, up to the present, there are still some problems to be overcome in regards to the technologies of flash memories.